What are the causes and treatments of flashing lights in the eyes?

Flashing Lights in the Eyes: Causes and Management

Immediate Assessment Priority

New-onset flashing lights require urgent ophthalmologic evaluation within 24 hours to rule out retinal tear or detachment, which can cause permanent vision loss if untreated. 1

Primary Causes

Posterior Vitreous Detachment (Most Common)

• PVD is the most common cause of photopsias (flashing lights), typically occurring between ages 45-65 when the vitreous gel naturally separates from the retina 1, 2
• Flashes occur due to mechanical vitreous traction on the retina during the separation process 3, 4
• 8-22% of patients with acute PVD symptoms have a retinal tear at initial examination 1, 3
• Even without initial tears, 2-5% will develop retinal breaks within the following 6 weeks 1

Retinal Pathology (Vision-Threatening)

• Retinal tears or detachment cause flashes, often accompanied by a sudden shower of floaters or peripheral visual field loss 1, 5
• Vitreous hemorrhage from torn retinal vessels presents as flashes with numerous new floaters 1, 2

Migraine-Related Photopsias

• Migraine with aura or migraine aura without headache can cause flashing lights 4
• These typically present as bilateral, zigzag patterns lasting 10-30 minutes, distinct from the unilateral arc-shaped flashes of PVD 4

Other Causes

• Trauma-induced PVD can occur at any age following direct ocular injury, surgical procedures, or intraocular injections 3
• Inflammatory eye diseases may cause cellular debris leading to visual disturbances 2

Red Flags Requiring Emergency Evaluation

Seek immediate ophthalmologic care if flashing lights occur with: 1

• New-onset floaters (especially a sudden shower)
• Peripheral visual field loss (curtain or shadow)
• Sudden decrease in visual acuity
• Recent eye trauma

Diagnostic Approach

Essential History Elements

• Timing and pattern of flashes (unilateral arc-shaped flashes suggest PVD) 3, 6
• Associated floaters or visual field loss 1, 7
• Recent trauma or eye surgery 3
• History of migraine headaches 4

Required Examination

• Visual acuity measurement in each eye 3, 7
• Pupillary examination for relative afferent pupillary defect 8
• Thorough peripheral fundus examination with scleral depression by an ophthalmologist skilled in binocular indirect ophthalmoscopy 1
• B-scan ultrasonography if media opacity prevents adequate retinal visualization 1, 3
• Assessment for vitreous pigment or hemorrhage (indicates higher risk of retinal tear) 1, 3

Management Algorithm

If Retinal Tear or Detachment Found

• Prompt intervention by an ophthalmologist experienced in retinal surgery is indicated 1
• Delay increases risk of permanent vision loss 8, 5

If No Retinal Pathology on Initial Examination

• Follow-up examination within 6 weeks is mandatory, as this is when retinal breaks may develop 1, 3
• Patients with vitreous pigment, hemorrhage, or visible vitreoretinal traction require closer monitoring 1
• 80% of patients who later develop breaks had pigmented cells, hemorrhage, or new symptoms 1

Patient Education

• Return immediately for increased floaters, peripheral vision loss, or decreased visual acuity 1, 3
• Most PVD symptoms diminish over several months without treatment 1
• Flashes from benign PVD typically resolve as vitreous separation completes 2, 7

Critical Pitfalls to Avoid

• Never assume flashing lights are benign without proper dilated fundus examination 1
• Failing to arrange follow-up within 6 weeks can result in missed retinal breaks 1, 3
• Underestimating the correlation between vitreous hemorrhage and retinal tears leads to delayed diagnosis 1
• Dismissing unilateral arc-shaped peripheral flashes as migraine without ophthalmologic evaluation risks missing PVD with retinal pathology 4, 6